Spray-gun-head construction



M. J. BINKS SPRAY GUN HEAD CONSTRUCTION Jan. 3, 19280 1,555,255

Filed Dec. 17. 1926 Patented. Jan. 3, 1928.

MELVIN J. IBINKS, OF OAK PARK, ILLINOIS,

60., OF CHICAGO, ILLINOIS, A

ASSIGNOR TO BINKS SPRAY EQUIPMENT CORPORATION OF ILLINOIS.

SPRAY-GUN-HEAD CONSTRUCTION.

Application filed December 17, 1926. Serial No. 155,466.

My invention relates to fiat-spraying appliances, such as the socalled spray guns commonly employed for projecting coating material in the form of a fan-like spray against the object which is to be coated.

Generally speaking, my invention aims to provide a simple and easily manufactured spray un head construction which will have the following important characteristics:

(1) An accurate alining of the air nozzle with the liquid nozzle, so that the annular sheath of air surrounding the initially projected stream of the liquid coating material will be uniform in thickness in any given cross-section of this stream. so that the axis of this sheath will be identical with that of the projected liquid, and so that the axes of the flattening air jets will intersect at a common point on the axis of the projected stream of liquid.

(2) An adequate supply of air for the outlet ports and an avoiding of tortuous paths for this air, so as to reduce the air pressure required for a proper atomization of the liquid into a spray of substantially uniform density.

(3) Straightness of the air outlet passages and easy of access to them, so as to fa cilitate both their manufacture and their cleaning.

(4) Ability to shift the plane along which the spray is flattened without varying the effectiveness of the air pressure.

Further and more detailed objects will appear from the following specification and from the accompanying drawings, in which Fig. 1 is a central, vertical and longitudinal section through the forward portion of a spray gun embodying my invention.

Fig. 2 is a front elevation of the same spray gun portion.

Fig. 3 is a rear elevation of the air-confining collar.

Fig. 4 is a side elevation of the air nozzle.

ig. 5 is a side elevation of the liquid nozzle.

Fig. nozzle.

Fig. 7 is a fragmentary central and longitudinal section through an alternative form of air nozzle and through the correspondingly modified collar.

Fig. 8 is a fra "mentary rear elevation of the air nozzle of ig. 7.

6 is a front elevation of the liquid Fig. 9 is an elevation of an air nozzle similar to that of Fig. 4, but provided with longitudlnal grooves adapting it for use with a retaining collar which has no longitudinal grooves in its bore.

In the embodiment of Fig. 1, the spray gun body 1 has the usual compressed-air passage 2 and liquid passage 3 extending to the forward end of this body, and the usual liquid inlet duct 4 leading to the liquid passage 3. Projecting forwardly from the gun body 1 in substantially axial alinement with the liquid passage 3 is a liquid nozzle 5,here shown as initially manufactured separately from the gun body and then tached to the latter, which the gun body forms the body spray gun.

The liquid passage 3 opens into the rear portion of the bore 6 of the liquid nozzle and this bore is contracted. at its forward end to form a small-diametered outlet bore 7 which extends through the cylindrical tip 8 of the nozzle. This outlet bore 7 is adapted to be opened or closed by longitudinally moving the usual needle valve 9, which valve extends substantially axially of the liquid passage 3 and the liquid nozzle, this valve having such a small diameter in proportion to its length that it can spring to insure a tight closure of the said outlet bore in case the latter is out of axial alinement with it. The part of the liquid nozzle behind its said cylindrical trip has its periphery of the general form of a forwardly tapering frustrocombined with member of the conical surface intercepted by longitudinal grooves which are spaced circumferentially of the nozzle and which extend for the full length of that surface.

Tightly fitted upon the forward portion of the liquid nozzle is an air nozzle 10 which has a relatively short forward portion 11 of its bore cylindrical and slightly larger in diameter than the outside diameter of the liquid nozzle tip 8, while the major [portion of the air nozzle bore flares rea-rwar ly and is a frustro-conical surface fitting the groove-intercepted frustro-conical surface of the liquid nozzle. The main part of the air nozzle has a forwardly tapering fiustroconical periphery intercepted by a periph eral' groove 12, and two air outlet ports 14 lead from diametrically opposite portions of this groove through the hunt and oi; the

threadedly atair nozzle, these ports having their axes intersecting at a common point 15 on the axis 46 of the air nozzle.

Owing to the above described fitting of the air nozzle on the liquid nozzle, the two nozzles are coaxial when assembled. Hence the outlet portion 10 of the bore of the air nozzle is concentric with the outlet tip 8 of the liquid nozzle, so that the sheath of air projected through the intervening annular space is a cylindrical tube coaxial with the two nozzles. Likewise, the intersection 15 of the axes of the flattening air jets is on the common axis of both nozzles and hence on the axis of the cylindrical stream projected through the outlet bore portion 7 of the liquid nozzle, so that the flattening of the spray will be symmetrical. I

To hold the air nozzle in its said tightly fitting relation to the liquid nozzle, I provide an air-confining collar 16 which isdetachably secured to the gun body and which has its forward portion tapering forwardly and bored to fit the general peripheral surface of the air nozzle. This collar bore is enlarged at circumferentially spaced portions by longitudinal grooves 17 which terminate back of the forward end of the collar.

The head parts are so proportioned in length that when they are assembled, the rear end of the air nozzle is disposed considerably forward of the front end of the gun body, thus leaving an annular space 18 of large capacity between the gun body and the air nozzle, which space opens into the grooves 9 and 17. By providing a plurality of grooves 9 on the liquid nozzle, I feed air to the annular outlet through passages of much greater transverse area than this outlet and hence avoid throttling the air pressure. Likewise, by providing a number of grooves 17 in the collar and connecting these operatively through the peripheral groove 12 on the air nozzle, I use this peripheral groove as an air storage chamber of exceedingly large capacity compared with the bores of the converging air ports 14. Consequently, I avoid the heretofore objectionable reducing of the effective pressure at these spray fiattoning air jets, so that I am able to operate my spray gun effectively at much lower air pressure than have heretofore been required.

T o insure an accurate directing of the converging air jets, I preferably provide the air nozzle with a pair of forwardly projecting lugs 19 through which the bores 1% respectively .extend, thereby increasing the length of these bores. The grooves 12 can rea ily be shaped so that needles run through the bores 14 will clear the rear walls of the grooves, thereby making it easy to clear these bores.

By providing long tapering surfaces for I the parts of the air nozzle which interfit respectively with the liquid nozzle and with the collar, I can secure tight seals between these parts. In practice, the threading of collar .and the gun body, but this will be directed rearwardly, so that it cannot in--.

terfere with the spray formation.

However, I do not Wish to belimited to the details of the construction and arrangement above described, since changes might obviously be made without departing either from the spirit of my invention or from the appended claims. For example, the circumferenti'ally extending groove might be formed in the bore of the collar, as shown at 12 in Fig. 7, in which case the longitudinal grooves 17 opening into it would be formed 1n the peripheral surface of the air nozzle, as shown in Figs. 7 and 8., Or, the passages for supplying air to the annular groove might be formed also on the part which has this groove, as shown by the longitudinal grooves 17 in the air nozzle of Fig. 9. In each case, this groove forms an air storage chamber to which air is supplied by passages which desirably are greater in number than the converging air ports. This ample supply of air for the said ports is provided regardless of the rotational position of the air nozzle, so that any spray gun will be equally efficient regardless of. the plane along which the spray is flattened and will not depend on a proper rotational alinement of any head parts.

I claim as my invention:

1. A flat-spray appliance comprising a body having a liquid passage and an air passage both open at the forward end of the body; a liquid nozzle projecting forwardly from the body and having its bore connected to the liquid passage, the liquid nozzle having a forwardly tapering portion disposed ahead of the body; an air nozzle having a tapering bore portion fitted upon the said tapering portion of the liquid nozzle and having an outlet bore portion freely surrounding the tip of the liquid nozzle, the air nozzle also having a forwardly tapering peripheral portion and having forwardly converging bores extending through itfrom its said peripheral portion to its forward end, a collar loosely threaded upon the body in approximate axial alinement with the liquid nozzle. the collar having a tapering bore portion fitted upon the tapering peripheral portion of the air nozzle; the said assemblage having rearwardly open longitudinal passages adjacent to the said interfitting portions of the air nozzle, and having an annular groove adjacent to and opening into the longitudinal passages which are adjacent to the interfitting parts of the air nozzle and collar.

2. A fiat-spray appliance comprising a body having a liquid passage and an air passage both open at the forward end of the body; a liquid nozzle projecting forconverging bores extending through it fromits said peripheral port-ion to its'forward end, a collar loosely threaded upon the body in approximate axial alinement with the liquid nozzle, the collar having a tapering bore portion fitted upon the tapering peripheral portion of the air nozzle; the said assemblage having longitudinal passages lead ing from the rearof the air nozzle to the space between the outlet bore portion of the air nozzle and the tip of the liquid nozzle,

the air nozzle having a peripheral groove into which the said bores open. and the collar having in its bore rearwardly open longitudinal grooves opening into the said peripheral groove.

3. A fiat-spray appliance as per claim 1, in which the rear end of the air nozzle is spaced from the forward end of the gun body by a considerable distance so as to provide an air chamber connecting the last named longitudinal grooves with the air passage in the body.

4. A flat-spray appliance as per claim 1, in which the rear end of the air nozzle is spaced from the forward end of the gun body by a considerable distance so as to pro vide an air chamber connecting the last named longitudinal grooves with the air passage in the body; the liquid nozzle having passages leading from the said air chamber to the space between the tip of the liquid nozzle and the outlet bore portion of the air nozzle.

5. In a flat-spray appliance, a body, a liquid nozzle projecting forwardly from it, an air nozzle fittedupon the liquid nozzle, a collar fitted upon the air nozzle and attached to the body, the air nozzle being spaced from the body to provide an air space therebetween and the body having an air supply duct leading to the said space; the air nozzle having a peripheralannular groove opening toward the collar and having a pair of converging ports leading from the said groove to the front of the air nozzle; there being air passages for connecting the said air,

space respectively with the groove and with a space between the forward portions of the two nozzles, the air nozzle being rotatable upon a loosening of the collar With respect to the body.

6. A head construction for a spray gun, comprising a body, a liquid nozzle extending forwardly from the body, a collar detachably secured to the body and freely spaced from the liquid nozzle to afford an air space around the liquid nozzle, and an air nozzle fitted upon the liquid nozzle and clamped upon the latter by the collar, the air nozzle having forwardly converging ports extending through it from diametrically opposite sides of that nozzle; the said assemblage being characterized by having a peripheral annular groove from which the said port-s extend fo'rw'ardly and by having a plurality of passages connecting the said groove with the part of the said air space behind the air nozzle.

Signed at Chicago, Illinois, December MELVIN J. BINKS. 

